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| n | a(n) |
|---|---|
| 1 | 12 |
| 2 | 144 |
| 3 | 420 |
| 4 | 1736 |
| 5 | 5856 |
| 6 | 15525 |
| 7 | 45738 |
| 8 | 115368 |
| 9 | 287174 |
| 10 | 700960 |
| 11 | 1620770 |
| 12 | 3730344 |
| 13 | 8345010 |
| 14 | 18340994 |
| 15 | 39838311 |
| 16 | 85088956 |
| 17 | 179931750 |
| 18 | 376333104 |
| 19 | 779411136 |
| 20 | 1601416922 |
| 21 | 3263854675 |
| 22 | 6606700688 |
| 23 | 13288445988 |
| 24 | 26569986742 |
| 25 | 52845438100 |
[12,144,420,1736,5856,15525,45738,115368,287174, 700960,1620770,3730344,8345010,18340994,39838311, 85088956,179931750,376333104,779411136,1601416922, 3263854675,6606700688,13288445988,26569986742, 52845438100] |